Characterization of low temperature GaAs antenna array terahertz emitters

We present a fabrication concept for photoconductive terahertz antenna arrays based on substrate-transferred thin films of low-temperature-grown GaAs semiconductor material. Adjacent array elements are physically decoupled by removing completely the photoconductive material in between. In contrast to former array devices based on intrinsic bulk GaAs substrates, this method allows the use of arbitrary carrier substrates with enhanced transmission properties. The emission characteristics of the device are investigated in terms of bandwidth, directivity, and saturation caused by charge-carrier induced field-screening effects. Screening-free operation is experimentally observed for an average optical power density below 2.2x10(-4) mW/mu m(2). (C) 2007 American Institute of Physics.